JPS6012979Y2 - Cooling/heating machine - Google Patents

Description

[Detailed description of the invention] This invention protects the compressor by suppressing the current so that the total operating current does not exceed a specified value, and also enables peak cut operation with high precision and sharpness. In addition, this cooling/heating machine eliminates the frequent repetition of starting and stopping and makes it possible to efficiently perform stable heating operation under conditions close to the limit value. Regarding the control mechanism.

・□In a heating machine that uses a compression refrigeration cycle, if the compressor motor becomes overloaded or locked, excessive current flows through the power distribution system and the motor itself overheats. There is a risk of causing

□1. Simultaneous operation of a large number of seed heaters may cause a sudden load and adversely affect the power transmission system.□1. From the standpoint of protecting the motor and wiring system and cutting peaks, prevent large currents exceeding the specified level from flowing through the electrical wiring for the heater.

It is normal to do so.

1. As a means for suppressing overcurrent, 1. Normally, a pie-metal type overcurrent relay is used to activate the overcurrent relay and stop operation due to overcurrent, but 1. , generally have an automatic return structure, so they are frequently stopped and started.

, At this time, the overcurrent, S, is greatly affected by the large variation in operating characteristics, and by the ambient temperature;
．． In addition, there was a problem that the protection function was not completely perfect due to various reasons such as the current value decreasing as the temperature of the coil increased and relay activation being delayed.
・ ・□, ・On the other hand, some proposals have been made in which when an overcurrent relay is activated, a self-holding circuit is used to forcibly continue to stop the operation, and the power cannot be reenergized unless the operator resets it. The reality is that it is not widely used in general household air conditioners because it is disadvantageous and difficult to handle.

Focusing on the fact that conventional protection devices have various deficiencies in practical terms, the present invention provides a new air-conditioning/heating machine with a protective function that can eliminate the above-mentioned conventional deficiencies. The characteristics of this system are as follows:
It determines whether the excessive current b (appears transiently, such as a starting current, and does not lead to an abnormality), and in the event of an abnormality, cuts the auxiliary electric heater for heating to reduce the operating current. In addition, in the event of an abnormality due to overcurrent in the compressor motor, the compressor will also be stopped and brought to a complete standstill.
Furthermore, when restarting the system, the compressor is first started after pressure equalization of the refrigeration circuit is completed, and then the auxiliary electric heater is energized to prevent the current from increasing excessively during startup.

The present invention will be further described in detail below with reference to the accompanying drawings.

The figure is an expanded view of the electrical circuit of the cooling/heating machine of the present invention. Although not shown, this cooling/heating machine is a reversible refrigeration system consisting of a compressor, a four-way selector valve, an indoor coil pressure reducer, and an outdoor coil. It consists of a reversible refrigeration cycle and an auxiliary electric heater for heating attached to this reversible refrigeration cycle, and when operating the heating when the outside temperature drops, the compressor motor 1, the blower motor 2 are operated, and the four-way switching valve is activated. The operation to the heating cycle side by de-energizing the solenoid 3 and the energization of the auxiliary electric heater 4 are performed by operating the operation switch 5. I am trying to run the heating operation.

. The electric circuit consists of a power circuit to which a commercial voltage is applied and an electronic circuit to which a low voltage is applied.
, electric heater 4:, operation switch 5, electromagnetic relay for compressor 10, electromagnetic relay for electric heater 11, room temperature thermostat 12
The electronic circuit consists of a current detection circuit 6, a starting compensation circuit 7, an overcurrent relay circuit 8, and a heater stop circuit 9.

This electronic circuit is the main part of this invention,
Carry out bone charcoal sequentially for each circuit.

(a) Current detection circuit 6, 1 A small secondary current proportional to the current is extracted by a current transformer 14 interposed in the bus W through which the combined operating current of the cooling/heating machine flows, and after rectifying this into direct current. , is converted into a potential E□ proportional to the current, and the potential E0 and a reference potential E2 corresponding to a set current smaller than the overload current are applied as inputs to the operational amplifier 9P□. .

This detection circuit 6 determines whether the total operating current is larger or smaller than the set current, and when it is large, the operational amplifier OP1
It outputs a logic output rLJ from , and conversely, when it is small, it outputs a logic output r″H.

(b) Starting compensation circuit 7, coil 10c of electromagnetic relay 10 for compressor, transistor T2. T3, a charging/discharging circuit including a diode D8, a capacitor Ct2, and a resistor Rt2, and an operational amplifier O.
The transistor L connected in series with the coil 10C becomes conductive when the base potential via the diode D becomes high, and functions as a switching element that applies a specified DC voltage to the coil 10c.

On the other hand, the transistor T3 becomes conductive when the transistor T2 is non-conductive (that is, when the coil 10c is in a demagnetized state), lowers the input potential of the operational amplifier OP3, and sets its logic output to 'L', thereby reducing the diode D7. The base potential of the transistor T2 is lowered to maintain the non-conducting state of the transistor T2.

In the operational amplifier OP3, the reference potential E4 divided by the resistors R, , R, is applied to the input terminal (2), and the charging fourth position E3 of the charging/discharging circuit is applied to the e input terminal, so that E4>Es
When E4<Es, a logic output rHJ is output, and when E4<Es, a logic output 1LJ is output, and this logic output is passed through a diode D2 interposed in the opposite direction to the heater stop circuit 9, which will be described later.
is connected to the input end of the

In the charge/discharge circuit, when the transistor T3 becomes non-conductive,
That is, when the transistor T2 becomes conductive and the coil 10c is excited, the capacitor CT2 is immediately charged via the resistor R1R3 and the diode D8, while the transistor T3
When the coil 10C becomes conductive, that is, the transistor T2 becomes non-conductive, and the coil 10C is demagnetized, the charge in the capacitor CT is gradually discharged by the resistor Rt2, and after about 3 minutes, the potential E3 becomes less than the potential E. Operational amplifier OP3
A logic output r″HJ is output from the .

As is clear from the circuit configuration above, when the coil 10ε is demagnetized and the compressor stops, the startup compensation circuit 1 changes the logic output of the operational amplifier mps to 1LJ, and the charging/discharging circuit starts discharging. Coil 10 by output r″LJ
□C demagnetization is forcibly held for 3 minutes, then logic output 1″H
Since the shift to J, this forced holding operates as if it were released, and therefore, even if a compressor operation command arrives within 3 minutes, the pressure #1 machine will not be started.

□The reason why we set the discharge time of the charging/discharging circuit to 3 minutes is because the refrigeration circuit is able to balance high and low pressures approximately 3 minutes after the compressor stops, so this discharge time constant is・You can set it based on the time required for low pressure balance.

□ (c) Overcurrent relay circuit 8~ Consists of a transistor T1, a charge/discharge circuit including resistors RtJ, Rt4, capacitor Ct3, and diode I-8, and an operational amplifier OP2. The logic output of the operational amplifier OP1 is 1LJ
It becomes conductive at r''H, and it becomes non-conductive at r''H, and functions to cause the subsequent charging/discharging circuit to charge when the transistor T1 is conductive and discharge it when it is not conductive.

On the other hand, in the operational amplifier OP2, the fourth charging position E5 of the charge/discharge circuit is applied to the e input terminal, and the reference potential E6 is applied to the ■input terminal, respectively, and when E5<Ee, the logic output r'' is applied.
HJ and a logic output 1LJ when Es > Ee.

In the charging/discharging circuit described above, when the transistor T1 becomes conductive, the potential of the discharging resistor Rt increases, so the capacitor C13 is charged via the resistor Rt3, and after about 4 seconds, the potential E5 becomes smaller than the potential E6. On the other hand, when the transistor T1 becomes non-conductive, the charge in the capacitor C13 is rapidly discharged through the diode and the discharge resistor Rt through the diode and L, so that E5<Ee. Therefore, the arithmetic divider OP2 functions to convert the logic output to 1HJ.

Note that the output terminal of the operational amplifier OP2 is connected to the input terminal of the starting compensation circuit 7 via a diode D6.

The overcurrent relay circuit 8 configured as described above operates as follows.

, the total operating current exceeds the set current and the operational amplifier opens □
As a result of the transistor T1 becoming conductive, the charging/discharging circuit starts charging, and after about 4 seconds, the logic output of the operational amplifier fP2 becomes 'H'.
Change from J to 'rLJ.

'□When the total operating current continues for 4 seconds at 7, the operational amplifier OP2 issues a logic output of 1LJ, so the input terminal of the start-up compensation circuit 7, that is, the base of the transistor T2, is shifted down to zero potential and the compressor is stopped. send a signal to do so.

On the other hand, when the total operating current decreases, the operational amplifier O immediately
The logic output of P2 becomes r″HJ, and the compressor stop command is released.

The charging time of the Omi charge/discharge circuit was set at 4 seconds because the duration of the transient current at the time of starting the compressor is less than 4 seconds, so the timing was set to avoid the hudging phenomenon caused by the transient current. It functions to determine whether the increase in the total operating current is due to an abnormality.

...) heater stop circuit 9, transistor T, coil llc of heater electromagnetic relay 11, and capacitor CT1. Resistor Rt1 and diode D,.

It is composed of a charging/discharging circuit including a transistor T5, and an operational amplifier OP, and the wiring procedure and basic operating mode are the same as the start-up compensation circuit 7, and the S charge/discharging circuit The discharge time of the startup compensation time (
3 minutes), the difference is that it is set to several minutes longer, for example, 7 minutes.

The input terminal of this heater stop circuit 9, that is, the forward-flow side terminal of the diode D connected to the base of the transistor T4, is connected to the output terminal of the operational amplifier OP and the output terminal of the operational amplifier OP3 via diodes D□ and D2, respectively. ing.

-The above circuit 911 operates as follows.

That is, unless the base potential of the transistor T4 is shifted down to zero potential, the coil llc will be energized to produce an electric current.
4 is energized.

On the other hand, when the logic output of operational amplifier JMoP1 or O12 becomes 1LJ, □In other words, if the total operating current exceeds the set value or until 3 minutes elapse after the compressor is stopped, Since the potential is shifted down, the coil 11.C is demagnetized and the electric heater 4 is de-energized, and this state is forcibly maintained for 7 minutes by the operational amplifier OP4'ρ logic output r''LJ/.

The charge/discharge time of 7 minutes is based on the start-up compensation time (3 minutes).
minutes)) the compressor is heated by the electric heater 4.
Drive in advance of 1. The time is not limited to 7 minutes, as long as it is a slightly longer time than the start-up compensation time and is set in consideration of not driving both the start-up compensation time and the start-up compensation time.

1. ,・Next, I will dream about the heating operation of a cooling/heating machine equipped with the above electric control system.

. (a) During normal operation, the current on the primary side of the current transformer 14 is less than the set current, so the logical output of the operational amplifier OP1 is 1HJS, and the logical output of the operational amplifier OP2 is 'H, &.

In addition, the diode D2. Transistor T2 via D9
．． T, respectively become conductive, and operational amplifiers OP3.
OP4 also roars rHJ.

□・(b) During peak cut operation ζ
, when the total operating current, that is, the primary current of the current transformer 14 exceeds the set current (e.g. 20A), E□>E2
→OP1. 'LJ-+ 11 c, 0FF-+ 1
1 c, OFF for 7 minutes, electric heater 4. will be de-energized and the electrical load will be reduced automatically, resulting in a 7-minute peak cut.

, in this case, 11 C, OFF
At the same time, the combined operating current usually decreases instantaneously and becomes less than the set current, so the output of the operational amplifier OP2 remains at rH and the compressor continues to operate.

Note that if the combined operating current is still larger than the set current even after 11C, OFF is performed, this is an overcurrent state, and the operation will be explained in the section 0 below.

,. After the electric heater 4 is reenergized, if the current exceeds the set current, a peak cut for 7 minutes is performed again.

(C) In the case of activation due to overcurrent, due to compressor restriction or overload operation of cooling/heating equipment,
If a total operating current larger than the set current still flows even after 4 seconds have elapsed after electric heater 4 was de-energized, □
, □ E□>E2→OPi 'LJ→11 c, 0FF-+
6> Es+op,, 'L, + 10 c, 0F
F-+ 1-, OC, ・0FI7 is held for 3 minutes → 10
C* ON → 4 more minutes, 7 minutes later, llc, ON
The compressor will automatically shut down completely, and the compressor will restart after 3 minutes.If there is no abnormality, the electric heater, 4
Power is applied to S.

The present invention has the structure and operation as described above, and has 1. It is equipped with a compressor and an auxiliary electric heater for heating.4.・It is a heating keyaki, and the total operating current 18 is the set current! ; a current detection circuit q that detects large and small Φ; a startup compensation circuit 7 that forcibly keeps the compressor stopped for a predetermined period of time when the IIJffi compressor stops; a current detection circuit q; is activated when it detects an overcurrent exceeding a set value, and if the overcurrent persists for a short period of time, which is a few seconds longer than the starting current duration of the compressor, the compressor is forcibly stopped. an overcurrent relay circuit 8,
When the current detection circuit 6 detects an excessive current exceeding a set value, it instantaneously de-energizes the auxiliary electric heater 4 and causes the activation compensation circuit 7 to release the power for the predetermined period of time. The present invention is characterized by a configuration in which the electric control system is equipped with a heater stop circuit 9 that forcibly holds the heater for several minutes, which is longer than the above.

. (a) When the total operating current exceeds the set value, stop the auxiliary electric heater and switch to heating operation using only the compression refrigeration cycle! By lowering the current, the power load can be reduced, peak cut operation can be reliably performed, and although there is a problem of insufficient capacity, heating operation can be maintained without significantly lowering the room temperature.

(b) If the increase in the clamping operating current is due to an abnormal condition such as a locking of the compressor, the compressor is stopped within a few seconds after the electric heater 4 power outage, so the protection function for the compressor is Everything is safe.

(c) □After the compressor is stopped, the restart of ρ is delayed by several minutes by the start-up compensation circuit 7, Uta.
This eliminates the inconvenience of excessive starting current flowing when the high and low voltages are unbalanced due to start-up and running, and not only protects the compressor, but also prevents undesirable problems such as voltage drops in the power distribution system. It is possible to prevent an unexpected phenomenon from occurring.

2) At startup, the compressor is first driven, and then, after the compressor motor current has stabilized, the electric heater 4 is energized, so the transient current value at startup can be kept low. becomes possible.

(E) Since the control method uses a control method in which the detection time of the combined operating current is short, e.g., f seconds, and the compressor is stopped for a long time, e.g., 3 minutes, the energization rate is about 1.7%, and almost no current is applied. Therefore, locking and protecting the compressor against overload can be done inexpensively and reliably.

As described above, the present invention has various excellent effects and is a very useful cooling/heating machine, and is especially suitable for implementation in a small household machine.

[Brief explanation of the drawing]

The figure is an exploded diagram of a control circuit related to the cooling/heating device of the present invention. 4...Auxiliary electric heater for heating, 6...
...Current detection circuit, 7...Start compensation circuit, 8...Song/overcurrent relay circuit, 9...
...Heater stop circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] A cooling/heating machine equipped with a reversible refrigeration cycle including a compressor and an auxiliary electric heater 4 attached to the reversible refrigeration cycle, in which the total operating current is larger or smaller than the set current. a start-up compensation circuit 7 that forcibly keeps the compressor stopped for a predetermined period of several minutes when the compressor stops; and a current detection circuit 6 that detects an excessive current exceeding a set value. an overcurrent relay circuit 8 that is activated when the current is detected and forcibly stops the compressor when the current continues for a short period of time, approximately several seconds, which is slightly longer than the starting current duration of the compressor;
When the current detection circuit 6 detects an excessive current that causes a set value, the auxiliary electric heater 4 is instantaneously de-energized, and this de-energization is controlled by the startup compensation circuit 7 for the predetermined time. The cooling/heating machine is characterized in that the electrical control system is equipped with a heater stop circuit 9 that forcibly holds the heater for several minutes.・ ・